Black box test--Decision table method

1. Decision Table

A decision table is a table that lists the various combinations of values and the corresponding output values of all inputs as conditions.

It is able to enumerate complex problems in all possible cases, concise and avoid omissions. Therefore, the decision table can be used to design a complete set of test cases.

Decision tables are usually composed of conditional piles (Conditions), condition items (Condition alternatives), action piles (actions), and action Entries 4 parts.

Condition Pile	Condition Item
Action Pile	Action Item

Condition Piles: List all possible conditions

Condition Item: Lists all possible ranges of values for conditions given by the condition pile

Action piles: List the actions to be taken

Action item: Indicates the action to be taken in the context of the various values of the condition item

2. Structure and simplification of decision tables

The <1> Construction decision table can take the following 5 steps:
(1) List all the condition piles and action piles.
(2) Determine the number of action rules (condition items).
(3) Fill in the conditions.
(4) Fill in the action item and get the initial decision table.
(5) Simplifying decision tables and merging similar rules.

Simplification of <2> decision table

For the decision table of n conditions, there are 2n rules (each with a true and false value), and when n is large, the decision table is cumbersome. When you actually use a decision table, it is often simplified first. The simplification of decision tables is the goal of merging similar rules. The even if table has more than two rules with the same action, and a very similar relationship exists between the conditional items and can be merged.

3. Use case analysis

Nextdate (int month, int day, int year) function specifies that three integers are entered: month, day, and year, and the output of the function is the date after the date entered. For example, when the input is March 7, 2006, the output of the function is March 8, 2006, and year satisfies 1920≤year≤2050.
The steps are as follows:

1) Construct decision table
M1={Month: 30 days/month},
M2={Month: 31 days/month, except December}, m3={month: December},m4={month: February} d1={Date: 1<= Day <=27}, d2={Date: Day =28}, d3={Date: Day =29}, d4={Date: Day =30}, d5={ Date: day = 31}
Y1={year: Leap year},y2={: Common year} NOTE: February: Common year 28 days, leap years 29 days conditional pile:
C1: Month in {M1,M2,M3,M4} One of the C2: date in {d1,d2,d3,d4, D5} One C3: Year in {y1,y2} One of the action piles:
A1: Impossible A2: Date increased by 1
A3: Date Reset (1) A4: Month increased by 1
A5: Month Reset (set 1) A6: Annual Increase 1

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C1: Month

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C2: Sun

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C3: Year

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A1: Impossible

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A2: Date +1

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A3: Date reset (position)

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A4: Month +1

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A5: Month Reset (position)

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A6: Year +1

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2) The test case is designed by the decision table and the test case table. ( Simplification)

Use Case number	Month	Day	Years	Expected output
1-3	4	12/28/29	2001	April 2001 13/29/30 Day
4	4	30	2001	April 5, 2001
5	4	31	2001	No way
6-9	1	15/28/29/30	2001	January 2001 16/29/30/31 Day
10	1	31	2001	February 1, 2001
11-14	12	15/28/29/30	2001	February 2001 16/29/30/31 Day
15	12	31	2001	January 1, 2002
16	2	15	2001	February 16, 2001
17	2	28	2004	February 29, 2004
18	2	28	2001	March 1, 2001
19	2	29	2005	March 1, 2005
20	2	29	2001	No way
21,22	2	30/31	2001	No way

Black box test--Decision table method